The invention relates to an electrical gas-blast switch by arc rotation due to the action of a magnetic field, having a sealed enclosure filled with a high dielectric strength gas, notably sulphur hexafluoride, in which there are disposed a movable main contact pivotally mounted on a first fixed spindle and operating in conjunction with a stationary main contact and a movable arcing contact pivotally mounted on a second fixed spindle parallel to said first fixed spindle and operating in conjunction with a rotation electrode, disposed coaxially inside a coil, electrically connected in series with the arcing contacts in an arcing circuit connected parallel to the main circuit which comprises said main contacts.
An electrical switch of the kind mentioned uses the energy of the arc to blow out the latter and therefore requires a relatively low operating energy, limited to the mechanical force of moving the contacts. The main contacts are protected by switching to the arcing circuit, this switching being able to be achieved either by arc migration or by arcing contacts connected in parallel with the main contacts and opening after the main contacts have separated. The use of arcing contacts connected in parallel with the main contacts prevents any arc or spark from forming on the latter when they separate, but requires perfect synchronization of the movements in order to avoid any premature opening of the arcing contacts or inversely on closing to prevent the main contacts from closing first. In addition to the problem of synchronization of movements, there also arises that of the electrodynamic repulsion effects exerted on the movable contacts through which the short-circuit currents flow requiring robust operating mechanisms.
The object of the present invention is to achieve a switch with a simplified operating mechanism capable of positioning and operating the main contacts and arcing contacts.